CHAP. x. CLIMATE AND HABITS OF THE HIPPOPOTAMUS. 179 



with in the lower level gravels of the Somme (p. 134), where 

 large blocks of sandstone seem to imply that ice once played a 

 part in their transportation, it may be well to consider, before 

 proceeding farther, what geographical and climatal conditions 

 are indicated by the presence of these fossil pachyderms. 



It is now very generally conceded that the mammoth and 

 tichorhine rhinoceros were fitted to inhabit northern regions, 

 and it is therefore natural to begin by asking whether the 

 extinct hippopotamus may not in like manner have flourished 

 in a cold climate. In answer to this enquiry, it has been 

 remarked, that the living hippopotami, anatomically speaking 

 so closely allied to the extinct species, are so aquatic and 

 fluviatile in their habits, as to make it difficult to conceive 

 that their congeners could have thriven all the year round 

 in regions where, during winter, the rivers were frozen over 

 for months. Moreover, I have been unable to learn that, in 

 any instance, bones of the hippopotamus have been found in 

 the drift of northern Grermany associated with the remains 

 of the mammoth, tichorhine rhinoceros, musk-buffalo, rein 

 deer, lemming, and other arctic quadrupeds before alluded to 

 (p. 157); yet, though not proved to have ever made a part 

 of such a fauna, the presence of the fossil hippopotamus north 

 of the fiftieth parallel of latitude naturally tempts us to 

 speculate on the migratory powers and instincts of some of 

 the extinct species of the genus. They may have resembled, 

 in this respect, the living musk-buffalo, herds of which pass 

 for hundreds of miles over the ice to the rich pastures of 

 Melville Island, and then return again to southern latitudes 

 before the ice breaks up. 



I am indebted to Dr. Falconer for having called my 

 attention to the account given by an experienced zoologist, 

 Dr. Andrew Smith,* of the migratory habits of the living 

 hippopotamus of Southern Africa (H. amphibius, Linn.). 



* Illustrations of the Zoology of South Africa : art. ' Hippopotamus.' 



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